Lung epithelial CYP1 activity regulates aryl hydrocarbon receptor dependent allergic airway inflammation

Abstract

The lung epithelial barrier serves as a guardian towards environmental insults and responds to allergen encounter with a cascade of immune reactions that can possibly lead to inflammation. Whether the environmental sensor aryl hydrocarbon receptor (AhR) together with its downstream targets cytochrome P450 (CYP1) family members contribute to the regulation of allergic airway inflammation remains unexplored. By employing knockout mice for AhR and for single CYP1 family members, we found that AhR-/- and CYP1B1-/- but not CYP1A1-/- or CYP1A2-/- animals display enhanced allergic airway inflammation compared to WT. Expression analysis, immunofluorescence staining of murine and human lung sections and bone marrow chimeras suggest an important role of CYP1B1 in non-hematopoietic lung epithelial cells to prevent exacerbation of allergic airway inflammation. Transcriptional analysis of murine and human lung epithelial cells indicates a functional link of AhR to barrier protection/inflammatory mediator signaling upon allergen challenge. In contrast, CYP1B1 deficiency leads to enhanced expression and activity of CYP1A1 in lung epithelial cells and to an increased availability of the AhR ligand kynurenic acid following allergen challenge. Thus, differential CYP1 family member expression and signaling via the AhR in epithelial cells represents an immunoregulatory layer protecting the lung from exacerbation of allergic airway inflammation.

Allergen-specific immunotherapy with Alutard SQ improves allergic inflammation in house-dust mites-induced allergic asthma rats through inactivation of the HMGB1/TLR4/NF-κB pathway

“…The interaction of HDM inhalation and airway epithelial cells directly caused airway epithelium dysfunction. HDM stimulates airway epithelial cells to release epithelial-derived cytokines, and recruit neighboring innate and adaptive immune cells including DCs, T-cells (such as Th2, Th1, and Th17), B-cells, eosinophils, and neutrophils, which are essential for asthma pathogenesis (12,30,31). Amongst these cytokines, IL-13, IL-33, TSLP, CCL5, CCL7, CCL17, CCL22, IFN-γ, IL-4, and several eotaxins strongly direct or support the development of a Th2 polarized inflammation (30,32).…”